Question

a study in el paso, texas, looked at seat belt use by drivers. drivers were observed at randomly chosen convenience stores. after they left their cars, they were invited to answer questions about seat belt use. in all, 75% said they always used seat belts, yet only 61.5% were wearing seat belts when they pulled into the store parking lots. why are the two percentages so different? the study was likely conducted when older people go to convenience stores. older people probably forget whether they were a seat belt or not. people likely claim to wear their seat belts because they know they should. they may be embarrassed to say that they do not always wear seat belts. there was a flaw in the random sample. they should have used a voluntary response sample. the percentages are different because the person recording if people wore seatbelts or not did not actually keep track of the actual number of people wearing seatbelts.

Explanation:

The two percentages (self - reported and observed) differ because people may claim to wear seat belts (due to social desirability bias - they know they should wear them and may be embarrassed to say they don't) but the actual observed percentage is lower. The option "People likely claim to wear their seat belts because they know they should. They may be embarrassed to say that they do not always wear seat belts." explains this discrepancy as self - reported data is influenced by people wanting to present themselves in a socially acceptable way, while the observed data is more accurate. The other options: the first option about the study being conducted when older people go to stores is not relevant to the difference in percentages; the second option about a flaw in the random sample and using a voluntary response sample is not indicated in the problem (the problem says drivers were observed at randomly chosen convenience stores and then left their cars to answer questions, so it's not a voluntary response sample issue); the fourth option about tracking the actual number is not the reason for the percentage difference.

Answer:

People likely claim to wear their seat belts because they know they should. They may be embarrassed to say that they do not always wear seat belts.